Tests were conducted on samples of alum, activated, and primary sludges obtained from water and wastewater treatment plants in southwest Virginia. The purpose of the testing was to determine if the sludges could be conditioned with polymers and still provide good filterability. Tests were conducted using a variable speed mixer with mixing intensities range from 246 to 2030 sec. Both anionic and cationic high molecular weight polymers were used during conditioning. The capillary suction time (CST) was used to measure relative change in filterability. Results indicated that alum, activated, and primary sludges can be conditioned to dewater readily during high-stress processes. In this regard, the standard jar test device was found to be inadequate in predicting polymer dose requirements in cases where high-stress dewatering processes are to be used. The most significant parameters governing high-stress conditioning were found to be polymer dose and total mixing energy input (Gt). It was discovered that once an optimum Gt had been established for a given polymer dose, any combination of G and t within the ideal range of G to t ratios could be used with no appreciable loss in filtering performance.